A vehicle communication interface, also referred to as a VCI, is used in the context of vehicle diagnosis. It is to be understood as a number of technical methods and applications that are utilized, for example, in fault analysis in the context of defects, in quality assurance, and in vehicle development. Vehicle diagnostic interfaces that are designed especially for vehicle diagnosis are used for data interchange with the vehicle or with components in the vehicle. These vehicle diagnostic interfaces can be constituted in various ways. A uniform communication interface, with which control can be applied to the different vehicle diagnostic interfaces, is therefore necessary.
Vehicle communication interfaces, referred to as VCIs, have been used for this for several years; they are utilized as an interface between at least one vehicle diagnostic interface and a computation unit, for example a personal computer (PC). The vehicle diagnostic interface in the vehicle is in turn connected to the control devices installed in the vehicle. A variety of interfaces are used in this context, for example high speed CAN, fault-tolerant CAN, single wire CAN, J1850, or OEM-specific interfaces. The Controller Area Network (CAN) is a serial bus system. “OEM” refers to an “original equipment manufacturer.” The terminal assignment or pin assignment of the vehicle diagnostic interface is defined in this context.
The pin assignment at the on-board diagnostic (OBD) plug is thereby also defined. The interface definition nevertheless leaves open options which result in OEM-specific assignments. It should furthermore be noted that older vehicles may not have an OBD plug, but may possess customer-specific diagnostic plug connectors.
The VCI contains a variety of transceivers and controllers in order to support the protocols recited above. The various pins of the transceivers can furthermore be switched via a so-called switch matrix to many pins of the OBD plug. The VCI can also be connected via specific adapter cables to other OEM-specific diagnostic interfaces.
Conventional VCIs may possess an analog to digital converter (ADC) which, inter alia, enables instrumental evaluation of transceiver signals. Additional diagnostic functions can be implemented therewith, for example a level check of signals for the correct High and Low levels. In positive logic, a High level is a logical 1, a Low level is a logical 0. This makes possible farther-reaching or deeper diagnosis than with simple digital evaluation of the transceiver signals. Early detection of high-impedance terminating resistors or leads, prior to total failure, thereby also becomes possible.
U.S. Patent Application Publication No. 2008/0004762 A1 describes an application-specific integrated circuit that is equipped with a vehicle diagnostic tool. The circuit encompasses a power supply module, a keypad interface, an oscillator, a microcontroller, a data connection controller, a vehicle interface, a display controller, and a memory interface.
China Patent No. CN 102591326 A describes an interface module for vehicle diagnosis. This module encompasses a switch matrix, a bus transceiver module, a selection module for serial data input channels, and an internal power supply circuit module.
The interface between the PC and the VCI can be embodied in wire-based fashion, for example with a Universal Serial Bus (USB) interface, a serial interface, or wirelessly, e.g. Bluetooth (BT), wireless local area network (WLAN), ZigBee, an industry standard for radio networks, or using other radio standards. The application software installed on the connected PC can configure the VCI, and via the VCI it retrieves, for example, diagnostic information from the control devices in the vehicle.
Present-day VCIs possess a discretely constructed switch matrix and transceivers implemented in part discretely. VCIs possess, in principle, further depicted functional groups.